The aim of this project it to investigate the fundamental time-resolved fluorescence processes induced by excimer lasers in order to develop quantitative criteria for reliable tissue characterization. Our approach involves time-resolved laser-induced fluorescence measurements for the purpose of identification of spectro-temporal patterns characteristic of different fluorophores, which can be used as "signatures" for unique and unambiguous characterization of various fluorophores (collagen, elastin, NAD and NADH). During this grant year, we developed a novel methodology/technology of laser-induced fluorescence attenuation using multiple optic fibers as a means of reliable on-line measurements of ischemia and hypoxia. The initial results have demonstrated the feasibility of such measurements, creating the prospect of useful applications in many surgical and diagnostic procedures.